kubernetes (GKE) nginx ingress looks fine but does not work

Question

I followed this guide to install the nginx ingress controller in the GKE.

Afterwards I followed this guide to create the ingress resource for my service.

I already setup my test app and service succesfully. Tested this by port-forwarding to the container.

Setting up the ingress seemed fine but I can't get access to it. When opening the external ip the following 502 error is print:

Error: Server Error

The server encountered a temporary error and could not complete your request.

Please try again in 30 seconds.

Please see the describe of the ingress:

│Name:         teamcity                                                                                                                           │
│Namespace:    default                                                                                                                            │
│Labels:       <none>                                                                                                                             │
│Annotations:  ingress.kubernetes.io/backends: {"k8s-be-31984--b5c10175cf4f125b":"UNHEALTHY"}                                                     │
│              ingress.kubernetes.io/forwarding-rule: k8s-fw-default-teamcity--b5c10175cf4f125b                                                   │
│              ingress.kubernetes.io/target-proxy: k8s-tp-default-teamcity--b5c10175cf4f125b                                                      │
│              ingress.kubernetes.io/url-map: k8s-um-default-teamcity--b5c10175cf4f125b                                                           │
│              kubectl.kubernetes.io/last-applied-configuration:                                                                                  │
│                {"apiVersion":"extensions/v1beta1","kind":"Ingress","metadata":{"annotations":{},"name":"teamcity","namespace":"default"},"spec":│
│{"backend...                                                                                                                                     │
│API Version:  extensions/v1beta1                                                                                                                 │
│Kind:         Ingress                                                                                                                            │
│Metadata:                                                                                                                                        │
│  Creation Timestamp:  2019-11-02T12:49:21Z                                                                                                      │
│  Generation:          1                                                                                                                         │
│  Resource Version:    553521                                                                                                                    │
│  Self Link:           /apis/extensions/v1beta1/namespaces/default/ingresses/teamcity                                                            │
│  UID:                 312aa230-fd6f-11e9-ad91-42010a84009d                                                                                      │
│Spec:                                                                                                                                            │
│  Backend:                                                                                                                                       │
│    Service Name:  teamcity                                                                                                                      │
│    Service Port:  8111                                                                                                                          │
│Status:                                                                                                                                          │
│  Load Balancer:                                                                                                                                 │
│    Ingress:                                                                                                                                     │
│      Ip:  35.190.86.15                                                                                                                          │
│Events:                                                                                                                                          │
│  Type    Reason  Age   From                     Message                                                                                         │
│  ----    ------  ----  ----                     -------                                                                                         │
│  Normal  ADD     18m   loadbalancer-controller  default/teamcity                                                                                │
│  Normal  CREATE  17m   loadbalancer-controller  ip: 35.190.86.15   

Additionally here is my yaml file for the whole mashup:

---
apiVersion: apps/v1
kind: Deployment
metadata:
  name: teamcity
  labels:
    app: teamcity
spec:
  replicas: 1
  selector:
    matchLabels:
      app: teamcity
  template:
    metadata:
      labels:
        app: teamcity
    spec:
      containers:
      - name: teamcity-server
        image: jetbrains/teamcity-server:latest
        ports:
        - containerPort: 8111
---
apiVersion: v1
kind: Service
metadata:
  name: teamcity
  labels:
    app: teamcity
spec:
  type: NodePort
  ports:
  - port: 8111
    targetPort: 8111
    protocol: TCP
  selector:
    app: teamcity
---
apiVersion: extensions/v1beta1
kind: Ingress
metadata:
  name: teamcity
spec:
  backend:
    serviceName: teamcity
    servicePort: 8111

I'd like to know what I did wrong here.

Answer 1

You are using GKE ingress controller with that Ingress resource, not Nginx. And the prove is that it is creating all the resources to create a HTTP load balancer; forwarding rule, target proxy, url map, backend service.

You need to pass the annotation kubernetes.io/ingress.class: "nginx" to your Ingress resource to let it know it shouod use Nginx Ingress Controller.

Now, you are getting 503 for while because GCP load balancers do not start working right away. Probably after about 3-4 minutes you will get 200.

Answer 2

As you are using ingress, the nginx service will be exposed to LoadBalancer, and others can be kept on clusterIPs only.

You can change the service to ClusterIP type instead of Nodeport here and try framing your ingress rule this way -

apiVersion: extensions/v1beta1
kind: Ingress
metadata:
  annotations:
    kubernetes.io/ingress.class: nginx
  name: rule-name
  namespace: default
spec:
  rules:
  - host: hostname
    http:
      paths:
      - backend:
          serviceName: teamcity
          servicePort: 8111

---

In the current scenario,you have not mapped any hostname to your ingress rule and if you don't have one specifically, you can just use the DNS name mapped against your publicIP/ ExternalIP of nginx.